Chip carrier a chip module and method of manufacturing the chip module

ABSTRACT

A chip carrier for manufacturing a chip module ( 18 ), with a substrate and connection leads arranged on the substrate has connection leads designed like stripes and extending parallel over the substrate. The connection leads are electrically conductive connection strands ( 12, 13 ) placed on the substrate. The substrate is formed by a carrier film ( 11 ).

FIELD OF THE INVENTION

The present invention relates to a chip carrier with a substrate andconnection leads arranged on the substrate, wherein the connection leadsare designed like stripes and extend parallel over the substrate. Inaddition, the invention relates to a chip module manufactured using thechip carrier, and a method of manufacturing such a chip module.

BACKGROUND OF THE INVENTION

Chip modules are usually manufactured using chip carriers whose surfaceis provided with a printed circuit structure for connection withelevated contact metallizations of the chip. The use of printed circuitstructures manufactured in etching processes does enable any printedcircuit structures desired, in particular those with a complex design.However, just the provision or manufacture of the conventional chipcarriers independently of the actual contacting process with the chipfor manufacturing the chip module already requires a complex andcorrespondingly expensive procedure. The use of etching techniquesrequires an appropriate structure for the carrier layer of thesubstrate, which in addition to a so-called etch-stop layer must also beprovided with a lacquer coating when using lithographic processes fordefining the printed circuit structure.

Known from DE 195 41 039 A1 is a chip module with a chip carrier, inwhich the connection leads formed on an insulation layer extend in astripe-like design and mutually parallel over the insulation layer ofthe substrate, and are each allocated to an elevated contactmetallization of a chip. To manufacture the known chip module, theindividual substrates of the chip carriers are arranged on a continuoussubstrate carrier, which is connected with the individual substrates viathe connection leads extending continuously over the substrate carrier.In the known method, the film-like substrate carrier is used only toconnect the connection leads with the substrate.

Known from DE 196 01 203 A1 are a data carrier card and a method of itsmanufacture, in which the data carrier card consists of a flat,injection molded plastic card body with at least one recess, on whichthree dimensionally guided printed conductors are applied. A chip can beelectrically connected with the printed conductors in the recess, andthen have a protective layer cast around it to form the data carriercard.

EP 0 421 343 A2 describes a chip carrier for the connection andelectromagnetic shielding of a single chip. The chip carrier has acomplex, curved structure with discontinuous connection leads formed onthe surface of the chip carrier.

EP 0 682 321 A2 shows a chip carrier to be arranged in a card body. Thechip carrier exhibits a carrier substrate with connection leadsdiscontinuously formed on the surface.

EP 0 391 790 A1 describes a chip module or a method of manufacturing anencapsulated chip module with a chip, in which a structured metal filmis applied to a carrier film to form connection leads.

FR 2 756 955 A1 describes a method of contacting a chip with a coil on acard-shaped carrier material, which is provided with a printed boardarrangement in the form of a coil.

SUMMARY AND OBJECTS OF THE INVENTION

Proceeding from known prior art, the object of the invention is toprovide a chip carrier for a chip module or a method of manufacturing achip module, which exhibits a particularly simple design relative to theknown chip modules, and hence opens the door to particularlycost-effective manufacture.

This object is achieved using a chip carrier for forming a chip modulewith a substrate and connection leads arranged on the substrate. Theconnection leads are designed like stripes and extend parallel over thesubstrate. In the chip carrier according to the invention, theconnection leads consist of electrically conductive connection strandsplaced on the substrate, and the substrate is formed by a carrier film.

Designing the connection leads as connection strands that are completelyindependent of the carrier film makes it possible not to have tomanufacture the connection leads based on an expensive etchingtechnique. Therefore, the chip carrier according to the inventionconsists of a combination of a carrier film and connection strands,which each represent independent elements in the initial state, so thatno special technologies, e.g., the use of an etching process, arerequired for manufacturing the chip carrier, but rather a simpleconnecting or joining process, wherein the substrate is directly formedby the carrier film. Having the substrate serve as the carrier film alsoenables substrates with a particularly flat design.

In a particularly preferred embodiment of the chip carrier, the side ofthe carrier film opposite the connection strands is provided with atleast one additional conductive strand, in which the insulating carrierfilm is arranged between the connection strands on the one hand and theadditional conductive strand on the other, forming an intermediatelayer.

Adding this at least one conductive strand on the opposite side of thecarrier film yields a capacitor structure that is arranged in a parallelcircuit with the chip after the connection strands have been contactedwith a chip. Precisely in the area of transponder technology, thisspecial configuration of the chip module gives rise to the specialadvantage when contacting the connection strands with a coil unit thatthe range of the transponder unit formed by combining the chip and coilunit can be distinctly increased.

In particular with respect to the automated manufacture of chip modulesusing the chip carriers, it proves advantageous to provide theconnection strands at least sectionally with a connecting materialcoating for contacting with the contact metallizations of the chip, sothat the chip can be contacted directly on the connecting strands afterproviding the substrate without any additional intermediate step. Thisconnecting material coating can consist of a connecting solder coating,or a coating of electrically conductive adhesive or the like.

Providing the connection strands at least sectionally with a contactmetallization for contacting with the elevated contact metallizations ofthe chip makes it possible to obtain especially high-quality, i.e.,reliable, connections, in particular due to the surface quality of theconnection strands as unproved by the contact metallization. Otherwise,of course, connecting strands made out of copper or a copper alloy canbe used to produce a direct connection with the contact metallizationsof the chip, in particular if the contact metallizations of the chipexhibit a lead/tin alloy or similar alloys with a correspondingly lowmelting point.

If the connection strands of the chip are connected with the terminalsof the coil unit, the chip carrier can serve as the basic unit formanufacturing a transponder, wherein the basic unit need only beenhanced by contact with a chip.

Based on the chip module described above, it is also possible, asalready mentioned above, to provide a transponder module in which theconnection strands contacted with the contact metallizations of the chipare connected according to the invention with terminals of a coil unit.

In the chip module according to the invention, the contactmetallizations of the chip are contacted with the top side of theconnection strands of the chip carrier. In addition to the fact that thechip module can be manufactured with a simple flip-chip contact, thischip module structure offers the advantage of making the side of thesubstrate lying opposite the connection strands available for furtherapplications.

If the connection strands contacted with the contact metallizations ofthe chip are additionally connected with the terminals of a coil unit, atransponder module with an especially simple structure is obtained.

The method according to the invention of manufacturing a chip moduleinvolves the following steps:

-   -   applying at least two electrically conductive connection strands        to one side of the carrier film, so that the connection strands        lie parallel to each other in a single plane, and extend in a        planar direction over the carrier film, and    -   contacting contact metallizations of the chip with the        connection strands, so that a contact metallization of the chip        is contacted with a respective connection strand.

As already emphasized at the outset while describing the structure ofthe chip module according to the invention, the manufacturing process ischaracterized by the lowest possible number of steps, due to the factthat the substrate provided with connection leads is realized via asimple combination of connection strands with a carrier film, and thetype of contacting according to the invention enables a simple flip-chipcontacting.

If the connection strands are contacted with the coil unit before beingcontacted with the chip, a first portion of the manufacturing process,which can also be executed independently of the subsequent contactingwith the chip, yields an intermediate product in the form of a chipcarrier, which can be directly used for manufacturing transponder units.

One particularly economic vat of the method according to the inventioncan be implemented if the connection strands are continuously applied tothe carrier film, so that the connection strands and the carrier filmare provided as continuous strands, and moved continuously toward eachother in a contact area with the generation of an adhesion.

If the carrier film is provided with window openings at defineddistances before forming the contact area with the connection strands,so that the window openings in the subsequently formed contact area arecovered by the connection strands while forming pocket-like contactreceptacles, it becomes possible to manufacture a chip module evenwithout the influence of a continuous process, in which the contactmetallizations of the chip are contacted with the bottom side of theconnection strands, and the chip itself is located on the side of thecarrier film opposite the connection strands.

Therefore, this method variant enables the manufacture of an especiallyflat or thin chip module.

A chip module with a capacitor structure can be manufactured in anothermethod variant by placing at least one additional electricallyconductive counter-strand on the side lying opposite the side intendedfor applying the connection strands. This process can take place beforeor after applying the connection strands on the carrier film.

One particularly easy and hence cost-effective way of implementing themethod is made possible by applying the connection strands and/or atleast one counter-strand on the carrier film in a lamination process. Inthis connection, it is also advantageous to use a hot-melt coating toform an adhesion between the connection strands and/or the at least onecounter-strand and the carrier film.

An embodiment of the chip module and a variant of the method ofmanufacturing the chip module shall be explained in greater detail belowbased on the drawings.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a top view of a chip carrier for manufacturing a chip module;

FIG. 2 is a view of the chip carrier shown in FIG. 1 with a chip incontact thereupon to form a chip module;

FIG. 3 is a sectional view of a first embodiment of a chip module;

FIG. 4 is a sectional view of a second embodiment of the chip module;

FIG. 5 is a sectional view of a third embodiment of a chip module;

FIG. 6 is a sectional view of an electrical equivalent circuit diagramfor the substrate of the chip module shown in FIG. 5; and

FIG. 7 is a diagrammatic view of a device for performing a variant ofthe method of manufacturing the chip module.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, FIG. 1 shows a top view of asection of a chip carrier strand 10 with a carrier film 11 andconnection strands 12 and 13 applied to one side of the carrier film 11.

FIG. 2 shows the chip carrier strand 10 depicted in FIG. 1 with numerousspaced chips 14 contacted on the chip carrier strand 10. As evident fromFIG. 2, the chips 14 with their contact metallizations, also referred toas “bumps” in technical parlance, are placed in contact with connectionstrands 12, 13 in flip-chip technology in such a way that one bump 15 or16 is allocated to a connection strand 12, 13 in an electricallyconductive manner.

As indicated by separating lines 17 in FIG. 2, chip modules 18 aredetached from the composite chip module held together by the chipcarrier strand 10 via separating cuts through the chip carrier strand 10after the chips 14 have contacted the chip carrier strand 10.

FIG. 3 shows a sectional view according to intersecting line III—III inFIG. 2. As evident, chip 14 is in contact in flip-chip technology withits bumps 15, 16 on the connection strands 12, 13 of the chip carrier 19separated out of the chip carrier strand 10 along separating lines 17.In this case, the carrier film 11 forming the substrate of the chipcarrier 19 consists of kapton, whose top side is covered with theconnection strands 12, 13 made out of so-called E copper. To improve thesurface quality of the connection strands 12. 13, the latter are coatedwith a contact metallization in this case. Other electricallynon-conductive materials can also be used for the chip carrier 19 orchip carrier strand 10, e.g., epoxy glass, polyester, polycarbonate andpolyimide, wherein a flexible design of the carrier film 11, e.g., usingpolyimide, is advantageous, in particular when using a manufacturingprocess of the kind explained in greater detail below with reference toFIG. 7.

FIG. 4 shows a variant of a chip module 20 in which the chip 14 isplaced in contact with a bottom side 22 of the connection strands 12,13, as opposed to the chip module 18 shown in FIG. 3, where the chip 14is in contact with a top side 21 of the connection strands 12, 13.

To this end, pocket-like contact receptacles 23, 24 are formed in theareas of the carrier film 11 of a chip carrier 28 covered by theconnection strands 12, 13, and used to accommodate the bumps 15, 16 ofthe chip 14. Given the appropriate preparation of the surfaces ofconnection strands 12, 13, e.g., via contact metallization, the bumps15, 16 can be directly in contact with the connection strands 12, 13, ora contacting process as shown in FIG. 4 can be performed, in which aseparate bonding material, e.g., soldering material 25 situated betweenthe bottom sides 22 of the connection strands 12, 13 and the bumps 15,16 of the chip 14 is additionally provided.

FIG. 5 shows another embodiment of a chip module 26, in which, asopposed to the chip module 18 shown in FIG. 3, a counter-strand 27 isprovided on the side of the carrier film 11 opposite the connectionstrands 12, 13, which is applied to the carrier film 11 in the samemanner as the connection strands 12,13, and can consist of the samematerial as the connection strands 12, 13.

The structure shown in FIG. 5 of opposing connection strands 12, 13separated from each other by an insulating intermediate layer in theform of the carrier layer 11 on the one hand and the counter strand 27on the other yields an electric capacitor arrangement whose circuitdiagram is shown in FIG. 6. According to FIG. 6, the structure of thesubstrate 28 yields an electrical serial connection of two capacitorsarranged parallel to the chip 14.

FIG. 7 shows a possible variant for manufacturing a chip module, whereinthe system design shown in FIG. 7 enables in particular the manufactureof the chip module 20 shown in FIG. 4 in a continuous and interconnectedarrangement. To this end, the system diagrammatically shown in FIG. 7encompasses a supply roll 30 with carrier film 11 wound onto it, whichis unrolled in the direction of arrow 31, and wound up at the end of thesystem on a product roll 32. Located in the area between the supply roll30 and product roll 32 are two supply rolls 33 and 34 with wound upconnection strand 12 or 13. Located between the supply rolls 33 and 34on the one hand and the product roll 32 on the other is a laminatingroller 35. To manufacture a continuous, band-shaped and interconnectedarrangement of chip carriers 28 or chip modules 20, as shown in FIG. 4,

the carrier film 11 is clocked and advanced in the direction of thearrow 31 according to FIG. 7, wherein window openings are incorporatedinto the carrier film 11 at the prescribed clock rate at definedintervals via a stamping device 36 to form the contact receptacles 23,24 shown in FIG. 4. Downstream of the stamping device 36, the connectionstrands 12, 13are supplied to the carrier film 11 from the supply rolls 33, 34, andthen connected with the carrier film 11 in a roll slit formed by thelaminating roll 35 and a counter-roll 37 in a contact area 38. As aresult of this joining or connecting process, the chip carrier 28 shownin cross section in FIG. 4 is therefore generated in continuous formdownstream of the laminating roll 35, and wound on the product roll 32.The product roll 32 can now be used as a supply roll for a subsequentmanufacturing process for the continuous or clocked contacting of chips14 with the connection strands 12, 13, thus making it possible tomanufacture continuously interconnected chip modules 20 as shown in FIG.4.

To prepare for a subsequent manufacture of transponder units, coil unitscan also be contacted with the connection strands after the laminatingprocess. The coils can here be designed as desired. The coils can bearranged on a separate carrier, or have no carrier in a particularlyadvantageous variant, being applied directly to the carrier film andcontacted with the connection strands. In this connection, the use ofwire coils proves advantageous.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

1. A chip module, comprising: a chip carrier comprising a substrateformed by a flexible carrier film and connection leads arrangedexposedly on the surface of the substrate to be freely accessible, saidconnection leads comprising stripes and extend parallel over thesubstrate, said connection leads comprising electrically conductiveconnection strands arranged on said substrate in a single plane andextending in a planar direction over the entire substrate surface andhaving a longitudinal expansion flush with the substrate surface, saidelectrically conductive connection strands being independent andseparate elements from said substrate; and a chip having connectingsurfaces with elevated contact metallizations, said contactmetallizations being in contact with a top side of said connectionstrands facing away from the carrier film.
 2. A chip module according toclaim 1, wherein the connection strands are in contact with the contactmetallizations of the chip and are connected with the terminals of acoil unit.
 3. A chip carrier arrangement in accordance with claim 1,wherein: said carrier film and said electrically conductive strands havea flexibility to be provided in rolls.
 4. A chip carrier arrangementformed by the process steps comprising: providing a flexible carrierfilm having a longitudinal dimension; providing a plurality ofelectrically conductive connection strands, said electrically conductiveconnection strands being provided separately and independently from saidcarrier film; attaching said electrically conductive connection strandsonto said carrier film as stripes extending substantially in parallelover said carrier film, said electrically conductive connection strandsbeing arranged exposedly on the surface of said carrier film in asubstantially single plane and extending in a planar direction over saidentire longitudinal dimension of said carrier film; dividing saidcarrier film with attached said electrically conductive strands into aplurality of substrates, said dividing being transverse to saidlongitudinal dimension.
 5. A chip carrier arrangement in accordance withclaim 4, further comprising: providing a chip with contactmetallizations; connecting said contact metallizations with saidelectrically conductive strands.
 6. A chip carrier arrangement inaccordance with claim 4, wherein: said carrier film and saidelectrically conductive strands have a flexibility to be wound intorolls.
 7. A chip carrier arrangement in accordance with claim 4,wherein: said carrier film and attached said electrically conductivestrands have a flexibility to be wound into a roll.
 8. A chip carrierarrangement in accordance with claim 4, wherein: said attaching of saidelectrically conductive connection strands onto said carrier film isperformed with adhesive.
 9. A chip carrier arrangement formed by theprocess steps comprising: providing a carrier film having a longitudinaldimension; providing a plurality of electrically conductive connectionstrands, said electrically conductive connection strands being providedseparately and independently from said carrier film; attaching saidelectrically conductive connection strands onto said carrier film asstripes extending substantially in parallel over said carrier film, saidelectrically conductive connection strands being arranged on saidcarrier film in a substantially single plane and extending in a planardirection over said entire longitudinal dimension of said carrier film;providing a plurality of chips with contact metallizations; connectingsaid contact metallizations of said plurality of chips with saidelectrically conductive strands; dividing said carrier film withattached said electrically conductive strands and attached said chipsinto a plurality of substrates, said dividing being transverse to saidlongitudinal dimension said dividing being performed to place one ofsaid plurality of chips on each of said plurality of substrates,wherein: said attaching of said electrically conductive connectionstrands onto said carrier film is performed with adhesive; said carrierfilm and attached said electrically conductive strands have aflexibility to be wound into a roll.